A network generally includes a number of devices connected to allow inter-device communication. Networked devices are often provided by multiple vendors that have expertise manufacturing different types of devices. Networks and networked devices have become increasingly complex and thus, it has become increasingly important to be able to monitor the status and performance of all of the devices that are connected to the network. Accordingly, networks typically include at least one network management station that can be used to monitor and manage the network.
Generally, networks manage the transmission of data among the devices using a network protocol. While network communications take place in many ways, many networks use one of a few widely known standards that are known to facilitate efficient communication among unrelated devices. For example, networks throughout Europe commonly operate under the Common Management Information Protocol (CMIP), while use of the Simple Network Management Protocol (SNMP) is more common in the United States. The capabilities of a given network will typically be limited by the functionality that is supported by its communication protocol.
SNMP is a network communication standard that provides a data transmission protocol, a structure for an object-oriented management information database (MIB) and a set of well defined data objects. SNMP objects define the status and characteristics for a selected network device. They are identified by an object identifier (OID) that defines the path through the database structure that leads to the object. Each target device on the network runs a network agent that maintains a MIB of objects corresponding to discoverable information supported by that device.
To obtain device information, the network manager typically identifies the network agent running on the target device, determines the type of information maintained in the device and sends the network agent the OID for the desired information with an instruction to either get or modify the value of the object. The network agent responds by accessing its MIB and retrieving/modifying the value of the object corresponding to OID or if the OID is not recognized, sending the network manager an error message indicating that the requested information is non-discoverable.
To identify the all of the discoverable information for a target device, a network manager would have to walk through the objects in the MIB one-by-one using a string of “get-next” requests. More specifically, the network manager could send the network agent a “get” request that includes the first OID, then send repeated “get-next” requests to obtain all of the discoverable information for the target device. There is currently no way to obtain a list of all of the OIDs for the objects corresponding to discoverable information for a specified networked device in response to a network manager request.
Further, the MIB for each device is typically configured solely by the device manufacturer. Thus, while it may be possible to discover a significant amount of information about a device, the network manager cannot obtain any information that does not correspond to an object that the manufacturer has included in its MIB.
It would be advantageous to provide a way for a network manager to obtain a list of all of the objects for discoverable information supported by a specified target device and to be able to access information that is not originally associated with objects that are initially contained in the MIB for the device.